Regenerative furnace



May 16, 1950 s. s. KISTLER REGENERATIVE FURNACE 4 Sheets-Sheet 2 Filed March 17, 1948 5 SAA/ILJEL 5'. K/STLER S. S. KlSTLER REGENERATIVE FURNACE May 16, 1950 4 Sheets-Sheet 4 Filed March 17. 1948 Ewan/D12,

0 2L) 7/ w w a SAMUEL 5., K/STLER Patented May 16, 1950 UNITED STATES PATENT OFF ICE.

REGENERATIV E FURNACE Samuel S. Kistler, West Boylston, Mass'., assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts 7 Claims. 1

The invention relates to furnaces and contemplates a built-in regenerator.

One object of the invention is to provide a furnace with a built-in regenerator having low resistance to passage of air. Another object of the invention is to provide a compact apparatus of the character indicated. Another object of the invention is to provide a simple and easily con-- structed' furnace apparatus of the type indicated. Another object is to provide a furnace with builtinregenerator, the mechanical parts of which are readily accessible. Another object of the invention is to provide a furnace with. built-in regenerator of a revolving type which requires little mechanical power to operate.

Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of partsv as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated in the. following claims.

In the accompanying drawings in which is shown one of various possible embodiments of the mechanical features of this invention,

Figure 1 is a sectional view of a furnace constructed in accordance with the invention, the section being taken generally along the line l-l of Figure 3.

Figure 2 is an elevation of the fuel and air distributing mechanism looking in the direction of the arrows 22 of Figure I.

Figure 3 is a horizontal sectional view on an enlarged scale taken on the line 3-3 of Figure 1.

Figure 4 is a sectional view of the fuel valve on a further enlarged scale taken on the line 4-4 of Figure 3.

Figures 5 and 6 are vertical axial sectional views of the valve of Figure 4 looking in the direction of the arrows 5-5 and 6-6 respectively.

Figure 7 is a vertical" sectional view on enlarged scale of. the distributor which appears near the middle of Figure 4.

Figure 8 is a horizontal sectional view on an enlarged scale and looking upward along the line- 88 of. Figure 1.

Figure 9 is a fragmentary enlarged detail of the regenerator element of Figure 8.

Referring first to Figure 1, the furnace may be mounted on a base plate 50 made of iron or steel. towhich are attached four posts l l, likewise of iron or steel, supporting an iron or steel plate I2. Upon the plate [2 is constructed an arch l3 of refractory material, for example made up of two courses of bricks as shown. One end of the arch I3 is more or less permanently blocked by an end wall l4 made of brick, while, as shown in Figure 3,, the other or front end is blocked by a brick wall [5 the upper part or some portion of the upper part thereof bein removable in order to gain access to the ware when the furnace is shut down. The base It] is approximately square, the plate 12 is approximately square and as shown in Figure 2 the two sides of the archl3 plus the back wall l4 and the front wall t5 form a more or less square enclosure. However, within the scope of the invention other shapes could be adopted. The shape shown has the ad'- vantage that it is easy to construct and torepair and it is easy to remove and replace the front wall It. At the same time the arch i3 and the walls l4 and I5 provide a semi-cylindrical space which is excellent from the point of view of combustion and provides a large space for setting the ware. combustion go up and down along the inside of the arch l3 and provide radiant heat to all sides and the top of the Ware which should be set'inthe central partof the chamber.

Referring again to Figure 1, approximately in the center of the plate i2 is a circular opening 20 which is closed at the under side by a cylindrical box 2| made of steel suitably secured to the under side of the plate 12. Over the opening 29 is a refractory regenerator 25 which is disclosed more in detail in Figures 8 and 9 and which will be hereinafter described. This regenerator 25'- is shown as cylindrical in shape but it may be of other shape so long as it covers the opening 20*. Surrounding the regenerator 25 and between the straight legs of the arch l3 and of the wallsl4 and i5 is brick work 26 which may be sup-- pl'emented by cement wherever it is diihcult to make the bricks conform to the cylindrical surface of the regenerator 25.

The top of the brick work 26 together with the top of the regenerator 25 forms a flat top 29 over which pass incoming air and the outgoing" gases. Over this flat top 29 is located a refractory ware carrying plate 3|! preferably made of a single piece of vitrified refractory material such as of silicon carbide bonded with vitrified clay or other ceramic material. This plate 30 has on the under side thereof ribs 3i in the form of a cross the four portions of which are perpendicular to the surfaces of the arch I 3 and of the walls' M and I5 and meet the legs of the arch and the walls l4 and It at midpoints thereof. The plate 3E! is likewise in contact with the legs ofthe arch l3 and the end walls l4 and I5 and thus the plate 30 and the ribs 3! in the form of a cross divide the space between the under side of the plate 30 and the surface 29 into four substantially uniform compartments 32 which are approximately square in plan view and of moderate depth. Air is constantly entering two or three. of these compartments 32 and thence through That is to say, the gases of' holes 36 in the plate 30 entering the combustion chamber, and exhaust gases are constantly leaving by one or two holes 36 and one or two chambers 32. In coming air passes through the regenerator 25 in an upward direction and exhaust gases pass through the regenerator 25 in a downward direction. The portions of the regenerator 25 through which the air on the one hand rises and the exhaust gases on the other hand descend is ever varying as will presently be made clear.

Referring now to Figures 1 and '7, through the bottom of the box 2| extends the straight portion of a large air pipe 39 which is curved below the box 2| as shown in Figure 1 and which is connected to a suitable blower 49 providing a large volume of air under low pressure. Referring now to Figure '7, the pipe 39 may be secured to the bottom of the box 2! and sealed to the opening 4| therein through which it passes by means of a ring 42 welded to the bottom of the box 2| and having a beveled face 43 against which a soft metal ring 44 is pressed by a ring 45 secured to the ring 42 by means of bolts 46. The soft ring 44 contacts the pipe 49 as shown in Figure 7.

Extending through the curved portion of the pipe 39 as shown in Figure 1 is a sleeve 41 through which extends a vertical shaft 49 that is constantly rotated at a slow rate of speed by mechanism to be hereinafter described. Referring now to Figure 7, secured to the top of the shaft 48 is a spider 50 comprising a hub arms 52 and a cylindrical ring 53' which rests on top of the pipe 39. A sleeve 54 is secured by set screws 55 to the ring 53 and the sleeve 54 projects downwardly and surrounds the upper part of the pipe 39- thus to keep the spider 50 centered on the pipe 39. Referring to Figures 1, 7 and 8, welded to the upper edge of the cylindrical ring 53 all the way around it is a distributor 69 which includes a semi-circular flat plate 6| with a semicircular cut-out the edge of which is welded to the ring 53, a semi-circular shaped part 62 the bottom of which is welded to the remainder of the ring 53, a diametral vertical wall 63 welded to the part 62 and a semi-circular vertical wall 64 welded to the flat plate 6|. The walls 63 and 64 practically touch the under side of the regenerator 25 and as the distributor B9 revolves it delivers air to a constantly changing half of the regenerator 25.

Referring now to Figures 8 and 9, the regenerator 25 is preferably made up of a great number of hexagonal rods 65 of refractory material. Each rod 65 has a number of bores 66 extending therethrough; illustratively there may be seven bores 65 arranged as shown in Figure 9 to provide a large total interior surface area. These rods 65 may be made by extruding ceramic material and then vitrifying it. The hexagonal shapes permit close compacting of the rods as shown in Figure 9; the periphery of the entire mass is shaved before firing in order to make the regenerator cylindrical and any resultant grooves may be filled in with cement as shown at 61. The firing is preferably done after the green rods 65 have been assembled and pressed together; after firing there is provided a cylindrical regenerator block having a great number of holes 86 parallel to its cylindrical axis and well distributed throughout the mass. This regenerator block 25 is not only refractory but capable of absorbing and holding a great number of British thermal units or calories, that is to say a large quantity of heat. After the furnace has been operating for one-half revolution of the distributor 60, heat is imparted by the hot regenerator to the incoming cold air which is delivered by the pipe 39; at the same time the volume of the regenerator block 25 whose under surface is not within the area of the distributor 66 is acquiring heat from the hot exhaust gases. These hot exhaust gases enter the box 2| (but at a lower temperature than that at which they enter the regenerator '25) and are conducted to a chimney or stack by means of a large pipe 70 connected to the box 2|.

Referring now to Figures 2 and 8, mounted on the base plate I0 is an electric motor 15 having a stepped pulley 16 any groove of which may be connected by means of a belt 11 to the opposite groove of a stepped pulley 18 mounted on a shaft 79 of a speed reduction mechanism 80. This speed reduction mechanism 80 has an output shaft 8| upon which is mounted a bevel gear 82. Any type of speed reducing mechanism may be used which gives the desired ratio, and many types are on the market. Accordingly, since reducing gearing is a separate art, it is not deemed necessary to illustrate the details of such speed reducing mechanism herein. In the present case a mechanism 80 was selected which had a ratio of 900 to 1, that is to say for every 900 revolutions of the shaft 19, the shaft 8| revolved once. The gear 82 meshes with a bevel gear 83 which is on the lower end of the shaft 48. Since the diameter of the largest groove of each of the pulleys l6 and I8 is about twice the diameter of the smallest groove thereof, and since the bevel gears 82 and 83 have the same diameter, it takes between 450 and 1800 revolutions of the pulley I6 to produce one revolution of the shaft 48 and therefore of the distributor 60. The motor 15 was rated 1725 R. P. M. Therefore the distributor 60 may be made to rotate as slowly as once in every sixty-two and one-half seconds or as fast as once in every fifteen and seven-tenths seconds. The distributor can also be rotated at two other speeds intermediate these limits with pulleys l6 and 18 having four steps as shown. Obviously, in accordance with the invention other ratios and speeds can be adopted.

The sleeve 41 as best shown in Figures 1 and 2 is supported by a plate 85 in the nature of a table which has three legs 86 supported by the base I0. Thus the shaft 48 and the bevel gear 83 are supported and journalled. Meshing with the beveled gear 83' is an equal sized beveled gear 99 on the end of a shaft 9| of a fuel valve generally designated by the numeral 92.

Referring now to Figure 1, a fuel pipe 93' conducts fuel such as a combustible gas to the valve 92. Referring now to Figure 5, the valve 92 comprises a main octagonal casing 95 having legs 96 by means of which it may be bolted to the base plate It). The casing 95 has a cylindrical bore 91 straight through it, the bore having a horizontal axis. Integral with the shaft 9| is a cylindrical portion 99 closely fitting the bore 91. Integral with the cylindrical portion 98 is a hollow semi-cylindrical portion 99 whose outer cylindrical surface likewise closely fits the bore 91. Integral with the hollow semi-cylindrical portion 99 is a hollow fully-cylindrical portion I00 whose outer cylindrical surface also closely fits the bore 97. These portions 98, 99 and H10 constitute a revolving valve. Attached to one end of the cylindrical casing 95 by means of bolts I0! extending through a flange I02 thereof is a hollow cylindrical member I03 having a bore I04 of somewhat asoaeae less diameter than that of the bore 91. This member I03 is blocked at the right hand end, Figure 5, by a long hub I05 having a small internally threaded bore I06. The fuel pipe 95 is connected to the hollow cylindrical member I53 outside of an orifice I I through which gas or other fuel enters the valve 92. The gas has no outlet from the member I03 except through the wide" bore III in. the portion I00.

Referring now to Figure i, it will be seen that the semi-cylindrical portion 5!? always blocks one half of the circle of the casing bore $1 between the portions 08 and I00. Four large fuel ports I I5, IE8, I I1 and I I8 extend through the casing 95' and into the bore 91 between the portions 98 and Hit. It will be seen that as the semi-cylindrical portion 99 rotates, two and sometimes three of these ports are open while sometimes two and sometimes only one of these ports are closed. Connected to the ports IIEi, H6, H1 and H3 are threaded pipe ends HG, are, IZII and I22. Thus gas from the port I I0 is directed to two or three of these pipe ends.

Comparing now Figures 1, 3 and 4 the pipe end H9 is on an angle union I23 which is connected to a pipe 524 which is connected to a right angle union I25 which is connected to an outside pipe I 25 which is connected to a right angle union I21 which is connected to a horizontal pipe I23 which extends through the left hand leg of the arch I3 and terminates right under one of the holes 36 in the plate 30. Similarly, the pipe end I22 is on the end of an angle union IBII which is connected to a pipe ItI which is connected to a right angle union I32 which is connected to a pipe I33 which is connected to a right angle union I34 which is connected to a horizontal pipe I35 which extends through the right hand leg of the arch I 3 and terminates just under another hole 35 in the plate 30. The pipe end 3213 is on the end of a pipe Hi0 which is connected to an angle union Gnot shown) which is connected to a pipe (not shown) which is connected to a right angle union (not shown) which is connected to a horizontal pipe I extending through the left hand leg of the arch I3 and terminates just under a hole 36 through the plate 3! Likewise the pipe end I2! is on the end of a pipe I5t which is connected to an angle union (not shown) which is connected to a pipe (not shown) which is connected to a horizontal pipe I which extends through the right hand leg of the arch I3 and terminates just under a hole 35 in the plate 3! Each of the pipes I28, 35, and IE5 is plng tc". inner end and has near such end a hole in the top, numbered respectively I56, I51, I58 and I59 in Figure 3, to direct gas through the corresponding hole 36. In the position of the semi-cylindrical portion $8 shown in Figure 4., gas is flowing through the pipes I 35 and I28. In the position of the distributor 60 as shown in Figure 1, air is flowing through the chambers 32 which have the holes 35 acent t ese same pipes.

Referring again to Figure 5, the left hand end of the casing 95 is blocked by a plate I5!) fastened to the casing by bolts Ifil. The shaft SI extends through a bore I52 in this plate I50 and a suitable seal its in a countersunk portion I64 helps to prevent gas from escaping. I preferably provide means to control the flow of fuel gas and preferably without reducing the pressure inside of valve 92. Referring now to Figures l and 6, I provide a slidable pert covering valve member I10 which has a semi-cylindrical exterior surface I'II fitting the cylindrical surface 91. It likewise has two diametral plane surfaces I12 which engage: corresponding diametral plane surfaces I13 of thesemi-cyl'indrical portion 99. Normally, when the valve is wide open, the valve member I10 is beyond the ports H5, H6, H1 and H8. It will be observed that the valve member I10 is shown in full lines in Figure 4. In Figure 5, which shows a section of the valve member I18, it is seen to be at the left hand end of the portion 99. Means is provided for drawing the sliding valve member I19 over the ports H5, H5, H1 and H8 more or less. To this end, as shown in Figures 5 and 6, I provide a shaft I15 having screw threads I16 engaging the internal threads I05 of the hub I05. To the outer end of the shaft I15 is secured a turning knob I11 by means of a pin I18. The inner end of the shaft I15 has a head I00 which islocated in a bayonet slot I 8| of the sliding Valve member I10. In the position of the sliding valve member I10 shown in all the figures, the ports H5, etc. are fully open. But if the turning knob I11 is turned, the sliding valve member I12! will be moved, more or less, to cover more or less of the area of the ports H5, etc., up to complete closure thereof. In such a case of complete closure, the sliding valve member I10 would be in contact with the portion. I80. The shaft I15 extends through a seal I in a countersunk portion I85 in the hub I05.

Thus, while the valve member represented by the portions 98, 99 and IIII] is always rotating to change the distribution of the gas, the sliding valve member I10 is likewise rotating and may be manually adjusted to any position inside the valve 92 between a position Where it does not obstruct the ports I I5, etc. whatsoever and a position Where it virtually closes themv apart from slight leakage.

'Io lubricate the rotating members, I may provide channels I90, I9I, I52, I93 and I94 in the casing 95 all as clearly shown in Figures 5 and 6. The entrance channel I94 for the oil may be sealed with a plug I 95.

In order to load the furnace, access is gained to the chamber by removal of part or all of the front wall I5. Of course this wall I5 is removed at least in part at the completion of a vitrifying or other furnace operation for the removal of ware that has been vitrified or otherwise heat treated. Therefore the operator usually finds the front wall I5 entirely or partly missing, that is from the level of the plate 30 upward. His first job therefore is to set the green ware. This green were is set or stacked upon the ware carrying plate 30 in accordance with principles known in the ceramic arts. That is to say, batts and saggers can be used if and as desired.

The furnace having thus been charged, the operator proceeds to rebuild the front wall I5. He does not necessarily use any mortar, although he may if he desires to do so. Two courses of bricks can be used and so located as to minimize move-- ment of flame, gas or air through the wall. Two courses of bricks will adequately keep the heat from escaping from the furnace. In thus building up the wall, the operator will omit enough bricks to leave a small hand hole for lighting the furnace.

Referring now to Figure l, is will be seen that the exhaust pipe 10 is connected to the inlet side of a centrifugal blower 2013'. This blower 200 has an exhaust channel 2! which is connected to piping 202 leading to a smoke stack in the building. The blower 40 has an inlet 203 which takes air from the room or from outdoors and discharges it through a channel 205 which is connected to a curved pipe 296 which is connected to the pipe 39. Thus air is pumped into the furnace but by reason of the use of the exhaust blower 200, the pressure in the furnace chamber is or may be atmospheric. For this reason there will be no tendency of the gases to pass through the wall l which is not air tight, nor need there be any tendency for air to pass inward through the wall I5. I provide dampers 203 and 209 which may be of conventional type and which may be located in the pipes 206 and i0 respectively and by manipulation of these dampers, the operator can quickly check any indraft of air or exhaust of gases through the wall l5. That is to say, if air seems to be sucked into the furnace through the wall 15, turning of the the damper 209 to check the exhaust slightly is indicated. Whereas, if gas is escaping outwardly through the wall I5, turning of the damper 208 to check the blast of air into the furnace is indicated.

To light the furnace, first see that the knob IT! is in such a position that the sliding valve member I will allow some gas to enter the furnace. Then pass a lighted torch of some nature through the hole in the wall I5 and locate the flame over one of the holes 36. The gas should now be turned on using a hand valve 2| ll in the pipe 93. The air should not be turned on yet. If the gas does not light, shift the torch or taper immediately to another hole 36 and so on until the gas does light. Immediately the gas has lighted, throw the switches for the two blowers 40 and 206 and then check the front wall l5 to see if the draft is in or out and neutralize the condition as above explained. Now the furnace is in operation and the intensity of the heat may be adjusted by turning the knob I11. At any time the remaining hole in the wall may be plugged with bricks but perhaps it will be desired to leave it open for observation.

It will thus be seen that there has been provided by this invention a furnace with built-in regenerator in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. A regenerative furnace comprising a refractory structure forming a firing chamber, a refractory plate extending across the bottom of said chamber there being several compartments under said plate and holes through said plate from said compartments, a regenerator having a plurality of vertical passages under said plate communicating with said several compartments, a distributor under said regenerator formed to deliver air to some but not all of said passage at any given moment, means mounting said distributor for rotation whereby during the course of a revolution it delivers air through said passages to the compartments successively, means rotating said distributor, means delivering air to said distributor, rotary valve means, a pipe delivering fuel to said rotary valve means, pipes from said rotary valve means to positions adjacent the holes through said plate whereby to deliver fuel to different portions of the chamber successively, and means to collect the gases of combustion exhausted through said regenerator from said firing chamber via said compartments.

2. In a regenerative furnace as claimed in claim 1, the combination with the parts and features therein specified, of means for blowing air into the distributor, and separate means to withdraw combustion gases from the regenerator, whereby the firing chamber can be caused to operate while combustion is taking place at atmospheric pressure thus obviating a requirement of tightly sealing the firing chamber.

3. In a regenerative furnace as claimed in claim 1, the combination with the parts and features therein specified, of ribs on the under side of the refractory plate forming the compartments.

4. A regenerative furnace comprising a refractory structure forming a firing chamber, a refractory structure forming horizontal passages under said chamber, there being a communication between each passage and said chamber, a regenerator having vertical passages under said horizontal passages whereby a plurality of vertical passages leads to each horizontal passage but no vertical passage leads to more than one of the horizontal passages, a box under the regenerator, connected to exhaust, a distributor in the box and open at any moment to some but not all of the vertical passages, an air pipe leading to the dis tributor through the box, and means to rotate the distributor.

5. In a regenerative furnace as claimed in claim 4, the combination with the parts and features therein specified, of rotary valve means and connections to deliver fuel to different parts of said firing chamber successively.

6. In a regenerative furnace as claimed in claim 5, the combination with the parts and features therein specified, of means to blow air into the distributor and separate means to suck gases out of the box, whereby the firing chamber can be caused to operate while combustion is taking place at atmospheric pressure thus obviating a requirement of tightly sealing the firing chamber.

7. A regenerative furnace comprising a refractory structure forming a firing chamber, a regenerato-r thereunder, connections including a rotary distributor to direct air successively through diiferent portions of said regenerator to said chamber and to collect exhaust gases from said chamber successively through different portions of said regenerator, connections including a valve with a moving valve member to deliver fuel successively to different portions of said firing chamber, means for blowing air into the distributor, and separate means to withdraw combustion gases from the regenerator, whereby the firing chamber can be caused to operate while combustion is taking place at atmospheric pressure thus obviating a requirement of tightly sealing the firing chamber.

SAMUEL S. KISTLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 664,526 Blass Dec. 25, 1900 1,858,508 Kignell et al May 17, 1932 

